function addFoodQuantity(x){
    var quantity = document.getElementById('FoodQuantity' + x);
    quantity.innerText = (Number(quantity.innerText) + 1).toString();
    var total = document.getElementById("total");
    var sub = document.getElementById("foodPrice"+x.toString());
    total.innerText ="￥"+(parseInt(sub.innerText.split("￥")[1]) + parseInt(total.innerText.split("￥")[1])).toString();
    var totalQuantity = document.getElementById("totalQuantity");
    totalQuantity.innerText = parseInt(totalQuantity.innerText) + 1;
}

function subFoodQuantity(x){
    var quantity = document.getElementById('FoodQuantity' + x);
    quantity.innerText = (Number(quantity.innerText) - 1).toString();
    var total = document.getElementById("total");
    var sub = document.getElementById("foodPrice"+x.toString());
    total.innerText ="￥"+(parseInt(total.innerText.split("￥")[1])-parseInt(sub.innerText.split("￥")[1])).toString();
    totalQuantity.innerText = parseInt(totalQuantity.innerText) - 1;
}